


Brother, Sister, Lover, Mate

by lostinmymindforever



Category: Supernatural
Genre: Alpha!Dean, Alpha/Beta/Omega Dynamics, Beta!Sam, Crossdressing, First Time, Gender Confusion, Knotting, M/M
Language: English
Status: In-Progress
Published: 2012-11-20
Updated: 2014-03-17
Packaged: 2017-11-19 02:58:08
Rating: Explicit
Warnings: Underage
Chapters: 4
Words: 9,679
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/568289
Author URL: https://archiveofourown.org/users/lostinmymindforever/pseuds/lostinmymindforever
Summary: <blockquote class="userstuff">
              <p>It wasn’t until puberty that Sam realized that something wasn’t quite right. When all of Sam’s friends started growing breasts and having their periods, Sam started having erections and wet dreams.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> This is my first time writing anything like this.

It wasn’t until puberty that Sam realized that something wasn’t quite right. When all of Sam’s friends started growing breasts and having their periods, Sam started having erections and wet dreams. It was the summer after Sam’s 13th birthday that Sam finally decided to talk to Dean about the worries that troubled her. 

Dad was gone again, something that was commonplace in those days. Sam sat watching Dean out in the backyard, biting her lips and fidgeting, trying to figure out just how to ask Dean about what was wrong with her. Sam could tell when she caught Dean’s attention, walking back inside when he motioned to the house.

Sam sat down on the couch, biting her thumb nail. Dean walked inside, sweat covering his tanned flesh, the sight stirring up feelings of want in Sam. “Dean, can we, can we talk about something important, without it getting back to dad? There’s something wrong with me. I need, I need your help.”

Dean is instantly worried, rushing over to the couch, kneeling in front of Sam, running his fingers through Sam’s long brown hair. He tilts Sam’s face up, getting lost in the younger Winchester’s hazel gaze, “Sammy, what’s wrong? Tell me. I need to know so I can fix this.”

Sam wrapped her arms around Dean’s shoulders, crying softly, “There’s something wrong with my body, Dean. I’m not right. Things aren’t happening like they are supposed to.”

Dean ran his hands soothingly along Sam’s back. He had always known this day was coming, had always known that one day Sammy would realize that he wasn’t a girl. Dean placed a kiss on Sam’s forehead, before looking his beloved little sibling in the eyes, “They are, Baby. Nothing is wrong with your body. You’re growing just like you should be.” He paused, running a hand across his face, “Thing is, Dad was just trying to protect you, protect us. That’s why you were raised the way you were. And I was so little I didn’t know any better, so I went along with it.”

“Dean, what?” confusion covered Sam’s face.

“See, I had a baby brother, Sammy. But after Mom died, and we went on the run, Dad thought it would be safer, you know, because they were looking for him and two little boys. He thought, he thought he could protect us if you were raised as a girl. No one was looking for a man and his son and daughter.”

Sam pulled back, jaw dropping in shock. “How? How could he do that to me? He knew how bad things have been for me lately. All my life has been a lie?”

Dean gently grabbed Sam, pulling her into his arms, “Sammy, he was trying to take care of you. Made me promise never to tell anyone. Made me promise never to tell you the truth unless you asked. Please, don’t hate me, Sammy. I just... I wanted to make sure you were okay.”

“Don’t hate you, Dean. You’re not the one who did this to me. It just... I don’t know how to be anything but a girl. What’s gonna happen now?”

Dean smiled, “I’ll take care of you, Sammy. That’s my job, isn’t it? Taking care of you, making sure you’re alright.” He looked Sammy over once, an idea popping into his head, “Let me get cleaned up and then we are going into town. Gonna get you some new clothes.”

Sam began shaking her head, “No, I don’t want to get boys clothes, Dean. I can’t, I don’t know how to be a boy.”

Dean chuckled, ruffling Sam’s hair, “Naw, gonna get you something pretty. Gonna need to get you a bra, teach you how to stuff it if you don’t want to have questions asked. We’ll have time to practice, getting you all pretty so when school starts in the fall no one will know. I only would have gotten you boys clothes had you wanted it.”

Sam smiled, pushing Dean away, “Go, get cleaned up, you smell.” She was giggling as Dean left the room to go shower and get changed. Her hand brushed across her lap, and the noticeable bulge in her skirt. She seemed to always be getting hard when Dean was close to her, something that never happened with anyone else.

Her hands idly played with the bulge, causing her breath to come faster. It felt so good. She had never touched herself like this before and was starting to wonder why not. Her hand moved under the hem of her skirt, cupping and caressing her flesh. Her breaths started coming faster, a moan slipping from her mouth. She shoved her hand down the front of her panties, the skin on skin contact driving her insane.

She pictured Dean’s face, biting her lips as she began to stroke herself with unsure movements. More images of Dean flooded her mind, Dean bent over the Impala working on fixing it up, Dean out in the backyard, doing yard work, his shirt long taken off, sweat traveling down his tanned flesh, Dean fresh out of the shower, towel wrapped around his waist, droplets of water falling tantalizingly down his chest.

Her hand wrapped tighter around her cock, as her strokes intensified, legs splayed wide, her skirt pushed up against her stomach, panties around her knees. Sam was moaning, eyes screwed shut as she touched herself, hand moving faster and faster along her length. Her other hand slid down between her legs, and she was shocked to feel how wet she was. She was amazed at the feeling, nothing had prepared her for this. Her fingers slipped easily inside of her, causing her to moan louder.

Dean stepped out of the shower, drying himself off quickly. He wrapped a towel around his waist and started heading towards his bedroom when the scent hit him. His cock hardened, and his mouth began to water. Licking his lips Dean moved on instinct, trying to locate where the scent was coming from. 

His jaw dropped when he saw Sammy spread out on the couch, hand stroking his cock, fingers inside of himself. Dean knew he shouldn’t watch, knew he shouldn’t want to go and replace Sam’s fingers with his own, but instinct was screaming at him to go take Sam. He had never known that Sam was a Beta, and the knowledge that he was was making Dean’s mind scream “Mine” “Mate” “Take”. 

He walked, as if on autopilot, towards Sammy, cock rubbing against the front of his towel. The sounds slipping out of Sammy’s mouth, the breathy sighs and moans, the sound of his fingers inside his wet opening, the sound of his hand flying over his cock, all of them sending pleasure through Dean’s body. He growled softly, hands pushing the towel off of his body before he dropped to his knees. He shoved Sam’s hands out of the way, mouth hovering over Sam’s cock. “Tell me I can do this, Sammy,” he whispered, his voice broken.

Sam moaned, eyes widening as Dean kneeled before him. She can see how hard Dean is and knows it’s for him. She nods, not trusting her voice. 

Dean grabbed Sam’s panties, pulling them off the rest of the way before leaning back down to take Sam’s cock in his mouth. Dean knows in that moment he has never tasted anything so perfect before. He knows he could get addicted to Sam’s taste. His fingers move to touch Sam, slipping inside the wet opening. He can feel Sammy clenching around his fingers, and moans around Sam’s cock, imagining how good it’s going to feel when he is buried inside of Sammy.

He knows the couch isn’t the best place for this, and pulls off of Sam with regret. Dean kisses the tip of Sam’s cock, before leaning up Sam’s body to give Sam a kiss. “Wrap your arms around me, Baby,” he whispers, grabbing Sam by the hips.

Sam doesn’t know what Dean is planning, but she trusts him, trusts him with everything. Her arms wrap around his neck, and he stands. She wraps her legs around his waist, letting out a squeal of happiness when Dean begins carrying her towards his bedroom. Dean sets her down on the bed, and quickly undresses her. He trails kisses along her body, taking time to suck and lick and tease her nipples, the nubs standing up in firm peaks. “Dean, please,” Sam didn’t know what she was asking for, but wanted more, anything.

Dean grinned, kissing Sam once more, “God, Baby, want you so much. You have no clue what you do to me. Tell me you want this, tell me you want me, Sammy. Want you so much, Baby Girl.”

The words drove Sam insane with want, hearing Dean call her that name, seeing the want in his eyes, knowing it was for her, “Dean, want you, wanna be your girl, want you so much.”

Dean swallowed, his hands trailing along Sam’s body. He moved Sam’s legs farther apart, fingers teasing once again at his slick opening. Sam was dripping wet, causing Dean to moan at the feeling. He kneeled between Sam’s legs, pulling them up onto his hips, and lined his cock up with the ring of muscle. He looked down at Sammy, his beautiful Sammy, his little brother, his Baby Girl, smiling as he entered him in one slow motion. 

Sam’s legs wrapped around Dean, ankles locked together on Dean’s ass, holding him in place. Dean’s cock filled her in ways she didn’t think were possible. Dean was being so gentle with her, rocking into her body, making her feel wanted and special. Her hands ran up and down Dean’s back, caressing his skin. Sam’s cock was pinned between their bellies, the friction driving her mad with pleasure.

“God, Sammy, so good. You are so perfect. Love you, Baby Girl. Need you,” he kissed Sam again, their tongues dueling back and forth in each others mouths. He pulled back, resting his head on Sam’s forehead, panting with want. He wanted to knot Sammy so bad, wanted to tie them together, claim Sam as his mate, but he wasn’t sure if Sam wanted that. Dean had remembered when he realized he was an Alpha, how he hadn’t told his father, afraid of the man’s reaction.

Alphas and Betas were rare. And as far as Dean knew there had never been an Alpha in his family before himself. Finding out that Sammy was a Beta had shocked him, shocked him and pleased him at the same time. He wanted to mate with Sam, truly mate with his younger sibling, make Sammy his and his alone for all time. But Sammy was so young, just 13, and Dean didn’t know if he had the right to make that sort of decision for him yet.

“Dean, please, more, need more,” Sam moaned, trying to force more of Dean inside of her. Something was driving her, an instinct that couldn’t be ignored. “Mate” the word came into her mind, rocking her to the core. She wanted Dean to make her his mate, never wanted anyone else to touch her or have her like this. “Dean, please, want you. Need you to mate with me, need it, you’re mine, don’t want anyone else to get to touch you.”

Dean groaned, hearing those words falling from Sammy’s mouth drove him insane with lust. His thrusts increased, hips slamming into Sam again and again. He could feel his knot beginning to form, and wanted so badly to bury it inside Sam. But he needed to be sure, “Sammy, we do this, fuck, Baby Girl, we do this, and there is no going back. You’ll be mine, always and forever.”

Sam groaned, fingers digging into the back of Dean’s neck, pulling him in for another kiss. “Yes, your’s, forever, Dean. Don’t want anyone else. Think about you, dream about you. Wanna be your girl, wanna be yours forever.”

Dean let out a pleased laugh, pounding into Sam again, he could feel his knot begin to swell, and each thrust was making it harder and harder to pull out all the way. He shuddered when he felt it reach it’s full size, tightly buried inside Sam’s body. Dean nuzzled Sam’s neck, kissing and licking the skin as his cock began to pulse inside of Sam’s body, filling Sam with his come. He shuddered, panting against Sam’s neck as he came. 

Dean had done his research, and knew they would be locked like this for at least a half hour if not more, so he rolled them, Sammy resting his head on Dean’s chest. Sam’s cock twitched, and he let out a howl as he came between them, his come covering both of their stomachs. Dean’s hands petted Sam’s hair, the long silken locks falling over them both. He held onto Sam, kissing the younger Winchester again and again, telling him how much he loved Sammy, how good Sam was being for him. 

They stayed like that for what seemed like an eternity, Dean coming inside of Sam again and again, Sam reaching his own orgasm at least four times as they lay tied. When Dean felt his knot begin to deflate, he pulled back a bit, but stopped when Sammy gave out a small pained moan of protest. Every few minutes he would try again, until it was small enough for Dean to pull out completely. 

Dean rolled Sammy on his back, moving to clean the boy’s chest and abs of the evidence of their coupling. He noticed Sam was hard once more, and took his cock into his mouth, sucking Sam down. Sam thrust up into his mouth, body so oversensitive that he came within moments. Dean swallowed every drop, moaning with pleasure as the taste filled his mouth. He moved farther down, his tongue snaking out to lick Sammy clean. He smiled against Sam’s flesh when he noticed only a small trickle had escaped his body.

When Dean was done, he crawled back up the bed, pulling Sammy into his arms. They napped, wrapped around each other.

After they woke from their slumber, Dean helped Sammy into the shower, cleaning his body, washing his hair, before quickly cleaning himself. They dried off and quickly dressed, pausing every so often to trade gentle kisses with each other.

Dean drove them into town, and parked in front of a clothing store. When they got out, he wrapped his arm around Sam’s shoulder, holding Sammy to his side. No one in town had met Sam yet, so Dean decided to act as if Sammy was his girl, which in many ways he was. They went inside, Dean following Sam as he looked through the clothes. He picked up every item Sam had smiled at, knowing that they had enough on the credit cards to pay for him to spoil his Sammy.

Getting underwear was a bit embarrassing, but Dean could see Sammy smile every time he’d pick up some lacey bra, or silky panties and give Sam an appraising look. They ended up spending a small fortune on clothes for Sammy, but Dean was happy to take care of his mate like that.

They stopped to get something to eat, Sam blushing every time Dean would feed him a mouthful off of his plate. To the outside world they looked like a normal teenage couple, and that was just how Dean wanted it to be. Sam was his, his mate, his lover, his girl, and Dean would be damned if he neglected him in any way.

When they got back to their house, Dean sat down on the couch, Sammy straddling his legs, raining kisses of thanks along Dean’s face and neck. His hands moved along Sam’s body, need filling him. He hadn’t realized just how much he could want someone, need someone, until that day. He was glad it was Sammy. It felt right, felt natural to have Sammy as his mate.

Sammy rocked down against Dean, her cock hard in her panties. She wanted Dean again, wanted to feel him inside of her, wanted to taste him, wanted anything he would be willing to give her. “Dean, want you. God, I want you,” she moaned, the front of her skirt tenting out due to her erection.

Dean groaned, cock twitching in his jeans at the words. He wanted Sam so bad. Wanted everything, wanted to give Sam everything. An idea hit him, “Mm, Sammy, wanna feel you inside of me. Do you want that? Want to fuck me, Baby Girl?”

Sam moaned, the thought of being inside of Dean almost overwhelming. She nodded, and grinned when Dean picked her up, carrying her towards his bedroom. “Want you Dean, want everything.”

Dean groaned, smiling at his mate as he reached blindly to his night stand. He pulled out a bottle of lube, handing it to Sammy. “Gonna need to get me ready for you, Baby Girl. My body doesn’t work like yours does.”

Sam nodded nervously, eyeing the bottle of lube, before returning her gaze to Dean. Dean had stripped naked, and was laying on the bed, legs spread wide. He opened the bottle of lube, pouring some on Sammy’s fingers before moving her hand to his asshole. Sam’s fingers brushed lightly against the tight ring of muscle, and her eyes widened with lust at the moan of pleasure that spilled from Dean’s mouth. She knew she must have been doing something right with how Dean moved to try and force her fingers inside of him.

Sam leaned up, kissing Dean as one finger slid past the tight ring of muscle, causing him to curse with pleasure. She was happy that she was making him feel so good, if the needy little moans coming from his mouth were anything to go by. Soon Sam was using two fingers, Dean telling her exactly what to do, how to stretch and open him for her. She worked slowly, grinning as he moaned so prettily, his head thrashing against the pillows.

“Sammy, please, want you inside of me,” Dean moaned, grabbing his legs, pulling them up to give Sam even more room. He hadn’t thought he could want anything as much as he wanted Sam inside of him, but the urge was overpowering. He watched as Sam poured some lube on his hand, covering his cock before tentatively placing the head at Dean’s hole. When Sam finally breached his body, Dean let out a string of pleasured curses, yanking Sam down for a kiss. “Mine, my Sammy, my Good Girl, my Mate. Come on, Baby Girl, fuck me. Fuck me, Sammy, need it, need you. Wanna feel you inside of me.”

Sam was lost when Dean started to babble, thrusting into him with one hard stroke. Dean seemed to arch off the bed, telling Sam how good it felt, how perfect. She began to thrust into him, feeling how he was tightening around her. She had never thought anything could feel like that, and couldn’t help but moan every time she bottomed out. Dean’s hands were all over her, touching and teasing and grasping at her. It was as if he was trying to pull her even closer than she already was.

Dean moaned, arching up into every thrust Sam made, trying to get Sam in ever farther. The head of Sam’s cock brushed against his prostate on every thrust. Dean’s cock was leaking steadily, a puddle forming on his stomach. He tangled his hands into Sam’s hair, pulling him down for a kiss. 

Sam groaned, feeling her cock begin to pulse inside Dean’s body, her come filling him. Dean was moaning under her, obviously enjoying what Sam was doing to him. She had never felt happier, the way Dean was making her feel, as if she was the most important thing in his world was a bit overwhelming.

As soon as he felt Sam’s orgasm finish, Dean gently pushed him off, moaning with loss as Sam’s cock slipped out of his body. He flipped Sam onto his back, shoving the Beta’s legs apart. He angled his hips, cock slipping easily inside of Sam. Dean rocked into Sam, kissing the younger Winchester passionately. He could hear Sam moaning again and again, and smirked when he felt Sam hardening once more. 

Dean groaned happily as he felt his knot begin to fill out. Nothing he had ever felt before was as good as being buried inside of Sam, but Dean was sure that was because he loved Sammy so damn much. He had never felt the need to knot anyone before, to tie himself to another, but here he was, about to knot Sam for the second time that day. He was addicted to Sam, Dean knew that as well as he knew his name.

Sam could feel Dean’s knot swelling within her, the feeling of fullness making her moan with pleasure. If she had her way, she would have Dean buried in her like this everyday, more than once. She had nothing she could compare the feeling to, but knew deep down that she would never want to feel another like this, never want anything more. Sam let out a soft yelp when Dean turned them on their sides, so caught up in thinking about him that the motion startled her. Dean kept kissing her, over and over, telling her how good she was, how perfect she was. She never planned on giving this up.

They must have fallen asleep while they were tied together, as the next thing Dean new it was the middle of the night. Sam lay in his arms, his back against Dean’s chest. Dean had obviously pulled out of Sam at some point, and part of him was screaming at him to take Sam once more. Sam rocked his ass back against Dean’s cock in his sleep, causing Dean to groan. He smirked, thinking it wouldn’t hurt anyone if he slipped back inside, back where he belonged.

“Do it, Dean,” Sam said sleepily, awoken by Dean watching her. “Want you in me all night, please.”

Dean groaned, kissing Sam’s neck as he slowly slid back inside. Where their other couplings had been intense and frantic, this one was one of comforting and love. Dean fell asleep, a smile on his face, buried inside his mate.


	2. Chapter 2

Sam and Dean fell into a routine, spending most of the day in bed together. Every few nights the two of them would go out on a date night, either to the movies or to dinner or just on a walk through the park. Their father hadn’t been back once over the summer, but he would call to check up on them every few days. 

Dean and Sam had decided to stay where they were as long as they possibly could. They liked the town they were living in, no one had a clue they were siblings so no one said anything about the two of them walking through town, holding hands, being overly coupley. Summer turned into fall, and the two of them began school once more. Dean was worried about not being able to protect Sam, as they were going to two different schools. 

Dean would pick Sam up from school every day, and greet him with a kiss as soon as he reached the car. Over the summer they had perfected Sam’s look, and so far no one had been able to tell that Sam wasn’t a girl. By the time Christmas break came around, Sam had convinced Dean to finish school, and Dean had agreed willingly, anything for his Sammy.

The year passed swiftly, and before he knew it, Dean was graduating from high school. John hadn’t been able to make it, as he was across the country hunting something or other, but when Dean walked across the stage to grab his diploma he had looked out to see Sam and Bobby smiling at him from the crowd. Dean and Sam celebrated the way they always did, Dean buried inside of Sam, knot tying them together, their hands caressing each others bodies.

Summer rolled around once more, and Sam and Dean had seen their father maybe six or seven times in the last year. But that didn’t concern them, not really, as he kept in contact with letters and phone calls. The few times he was home were horrible on them, they couldn’t be together how they wanted. Sam would sneak into Dean’s room on the nights John was there, and the two of them would do their damndest to keep their couplings quiet. The one time John had been around for almost a month had been the worst, and Dean had had to drag Sam off into the woods behind their house and take him there on more than one occasion. 

They knew their father didn’t have a clue of the change in their relationship, and were glad that they didn’t have to tell him yet, they knew the day would be coming soon though, when John would start to question them about why neither of them dated.

When the school year rolled around once more, Dean worried even more than he had the year prior. He had gotten a job, one that allowed him to be able to take Sam to school and pick him up everyday. About two weeks into the school year Dean had went to pick Sam up and saw a group of seniors surrounding him. He hopped out of the car, making his way towards Sam.

“Seriously, I am not interested. I am spoken for,” Sam said, repeating her words to the boys for what seemed the twentieth time in the last five minutes. For some reason they thought she was available and were trying to entice her to go with them. She let out a sigh of relief when she saw Dean striding up the stairs, practically throwing herself into his arms.

Dean glared, he should have known something like this would happen, as there had been a group of Alphas a year behind him in school the year prior. He wrapped his arms around Sam’s shoulders, leaving a territorial kiss along his neck. “Gentlemen, there seem to be a problem here?”

“No problem whatsoever, Winchester,” one of the boys sneered. He gave Dean a hate filled look, before returning his gaze to Sam, eyeing him up like he was a piece of meat.

“If you want to keep your eyes, I suggest you take them off my mate,” Dean growled, arm tightening around Sam. 

Sam rested her head against Dean, feeling safe in his arms. She could feel Dean’s hand begin to run along her back, the motion completely territorial. Her breath began to quicken as she began to harden, and her body began to get wet for him. She could hear muttered curses, and knew the other Alphas could smell her arousal.

Dean practically dragged Sam to the car, glaring at the other boys as if daring them to try and stop him. Dean drove home quickly, using all his control to prevent himself from just pulling over to the side of the road and fucking Sam against the side of the car. The Impala was barely parked, Dean dragging Sam into the house and shoving him down roughly onto the couch. He shoved Sam’s legs apart, shoving his skirt up, ripping his panties off of him. Dean kneeled in front of Sam, burying his face between his legs, his tongue snaking out to lick the sweet taste of arousal that spilled from Sam’s body.

Sam was moaning so prettily, and had yanked his shirt off, tossing it to the floor. Dean could feel Sam’s fingers tangle into his hair, holding Dean’s face in place. Dean’s tongue worked into Sam’s body, lapping up the addicting slick that was dribbling from his hole. 

Dean pulled back, panting with want and need. He shoved his jeans down, and slammed inside of Sam with one hard thrust. Seeing those other Alphas trying to take his Sammy had almost broken something inside of him. He had wanted to take Sam then and there, showing those bastards with utter certainty that Sam belonged to him. His cock slammed into Sam again and again, harder than he had ever fucked Sam before. He could feel his knot beginning to swell, and slammed it inside of Sam, causing the younger boy to almost come off the couch. 

Sam knew she was going to have bruises on her hips from their coupling, from how hard Dean was holding onto her. Usually he was so vocal when they had sex, but this time he was silent, save for growls and moans and his harsh pants of breath. She clawed at the back of his neck, knowing it was going to leave a mark, but couldn’t be bothered to care. Nothing had ever felt so intense. Dean’s cock swelled within her, tying them together. He kissed her again and again, saying one word again and again, “Mine”.

Dean lost track of time, not knowing how long they stayed like that, not knowing how many times he came inside of Sam. All he knew was that it was dark out, and Sam looked incredibly fucked out. He pulled out slowly, not wanting to hurt Sam. He placed a tender kiss on Sam’s lips, running his fingers through Sam’s long locks. 

Sam winced a bit, sore and tired, but feeling completely loved. Her hands reached up to cup Dean’s cheeks, and she watched him with a tender look in her eyes. Whenever she thought that she couldn’t love Dean anymore than she already did, he’d do something that amazed her and made her fall deeper in love with him. She loved that he never tried to pressure her into thinking of herself as male, even if she knew that’s how he thought of her. She loved how he took care of her, made her feel special and wanted, made her HIS GIRL.

Sam hadn’t wanted their coupling to end, it had been the most intense one to date. Seeing Dean so fiercely jealous and overprotective of her had driven her insane with want. Sam had wanted Dean to shove her against the wall and screw her then and there, claiming her where everyone could see it. Dean had fucked her like a madman, making her come again and again, until she was worn out from the sheer pleasure, and still he had fucked her, knotting her at least five times since they had walked in the door. 

“Dean, love you,” Sam whispered, brushing her lips against his. 

Dean smiled, moving to sit next to Sam on the couch, pulling Sam onto his lap. Dean groaned as he felt his cock begin to harden once more. He could see the devilish little smirk on Sam’s face, the one he always had when he was up to play with Dean. Dean stood, throwing Sam over his shoulder and rushing to his room. He tossed Sam down on the bed, grinning as he bounced a bit before he was all over him again. “Mine, only mine, Baby Girl,” Dean said, his voice rough as he crawled between Sam’s legs.

“Fuck me, fuck me, fuck me,” Sam chanted, legs spread wide. She could feel the tip of Dean’s cock teasing at her opening and bucked down, forcing the large member inside of her with a moan of pleasure.

Dean couldn’t say no to Sam, never had been able to, and he began thrusting into his mate with sure, steady motions. Sam’s legs wrapped around his waist, ankles locking together on Dean’s ass, holding him inside. Dean thrust into Sam, the need to take, the blind instinct to mark Sam as his, to claim taking over once more. “Mine, my Sammy, my Baby Girl, Mate,” his words were slurred with lust, and he kissed Sam’s kiss bruised lips hard.

His hands grabbed at Sam’s shoulders, holding him to the bed as he fucked him hard and fast. Dean could feel his knot beginning to swell, and cursed as he slammed it fully inside of Sam, locking them together once more. He was panting, sweat dripping off of his face as he rolled them so that Sam was on top, his cock spilling his seed into Sam steadily. Sam was moaning above him, and Dean smiled as he let out a small yell of pleasure as he came between them, come covering both of their chests. 

Dean wrapped his arms around Sam, kissing him on the forehead. They lay together, tied in the most primal of ways. Dean could hear Sam’s breath begin to slow, and knew that he would probably doze for a while, he always seemed to after Dean fucked him over and over. Dean smiled, loving it when Sam fell asleep still tied to him, resting on Dean, showing a level of trust that was staggering.

Dean must have fallen asleep himself, as the next thing he knew he was being woken to an angry shout, “What the fuck is going on here?” 

Dean looked up to see his father standing in the doorway, anger, shock, confusion written on his face. He could feel Sammy trying to pull away, but then heard a pained whimper come from him. They were still tied together, and there was no separating them, not yet. Dad could yell and scream all he wanted, but he couldn’t separate them, not now.

John had been shocked when he had walked into the house, the living room reeking of sex, clothes all over the floor. He had stormed to Dean’s room, assuming that Dean had brought someone home, angry that he could do that with Sam around. His anger had grown when he saw his children in bed together. 

When Sam had tried to pull off of Dean he had heard the sound, heard the pained whimper and his mind instantly started drawing conclusions. He nodded at his children, “When you can, meet me outside. I’m gonna air out the house. The three of us need to talk.”


	3. Chapter 3

John waited outside, running his fingers through his hair. He knew what he had seen, knew damn well why Sam had made the pained nose he had when he had tried to pull away from Dean. John had had no clue that either of his children were special. He had never heard of a Alpha or Beta in his family line, and had no clue if there had been any in Mary’s, but it was obvious that Dean was an Alpha. What he was doing sleeping with his 14 year old brother was beyond John, and he was angry. John was angry at Dean, angry at him for using Sam like that. Angry at himself for leaving them alone together as often as he did. 

It was almost an hour later when Sam and Dean walked outside, Dean’s arm wrapped tightly around Sam’s shoulder. John could see hickies and bite marks covering his youngest’s neck, could see the almost territorial way Dean was holding him. Before he could start yelling, before he could say a single word, he heard Sam whisper.

“Don’t be mad at him, Dad. Please, don’t be mad. This isn’t his fault.” Sam was clinging to Dean, trying to get as close to him as possible.

John glared, “It’s not his fault? Sammy, you are 14, this isn’t right. Dean shouldn’t have forced you into this.” He waved between the two teens.

Sam started laughing, causing John to give a confused look, “Dad, he didn’t force me. My mate didn’t do anything I didn’t want him to, need him to.”

‘Mate’, the word rattled in John’s head over and over again. Sam and Dean were mates,which meant, which could only mean one thing, “You’re...”

Sam nodded, biting her lip, “Yeah, I am. I’m a Beta. Dean... Dean’s my everything, Dad. Please, try to understand. He didn’t force anything on me, didn’t try to make me what I wasn’t.” She looked up at Dean, a smile on her face. 

John swallowed hard, he knew that smile, had seen it on Mary’s face when she would look at him. The smile spoke of love and adoration, it was a smile of someone completely and utterly in love. As much as everything inside of him was screaming that this was wrong, that they were brothers, that they shouldn’t be together like that, John knew that there was nothing he could do to change things. Not if they were mated.

John had never met an Alpha before as far as he knew, but he knew about them, everyone did. When an Alpha and Beta mated it was permanent, it was for life, and nothing could separate a mated pair. John knew that an Alpha would do whatever it took to take care of, to protect their mate, that they loved them more than anything else in the world. If you messed with an Alpha’s mate you had better expect a beat down at the very least. 

He knew that unmated Betas tended to have terrible lives, their submissive nature making them easy targets for violence and being abused in other ways. Finding out that his youngest was a Beta should have terrified him, he already was scared for Sam’s life, knowing the thing that killed his mother was still trying to find him. John knew though that Dean would do whatever it took to protect Sam, just as he always had. 

John was watching how the two were standing with each other, Dean standing slightly ahead of Sam as if trying to put a barrier between John and Sam. It broke his heart to see Dean thinking he would ever contemplate hurting Sam. “How long has this been going on?”

“A year, well a little over a year now,” Dean answered, watching the play of emotions on his father’s face. He saw the resigned look on John’s face and knew that his father knew he couldn’t make them stop being together. 

“Have you... have you been using protection? Sam’s so young...” John didn’t know how to continue that thought, not out loud at least. There were some things he just couldn’t say to his children.

Sam and Dean both got guilty looks on their faces, and John knew right away that they hadn’t been taking any precautions, had just been letting things run their course naturally.

Sam started biting her thumbnail, blushing as she looked at her father. While it was true that she and Dean had never used protection of any kind she hadn’t ever thought about the possibility of needing it. But now, hearing her father ask Sam knew that they had been lucky so far. For some reason she had never even thought to go on any sort of birth control, to have Dean use condoms. Part of her wanted to have Dean’s child but she knew that she wasn’t ready for that, wasn’t sure if she would ever be.

Dean swallowed, looking from his dad to Sam, hands lightly caressing Sam’s back. Part of Dean wanted to drag Sam back inside, claim him again and again, fill him so full of his seed that he conceived. He looked at his father and could see John shaking his head, knowing damn well that his dad must have picked up on what he was thinking.

“I worry about the two of you, you do know that right?” John asked, looking back and forth between them. All the anger had drained from his face and he watched his boys with a look of fondness and sadness.

\---

It was later, and John couldn’t sleep. Sam and Dean had went to bed some time earlier, both of them going to their own rooms. John tossed and turned, trying to come to terms with everything he had learned since he got home. He heard quiet footsteps, and went to his bedroom door making as little noise as possible. He watched as Sammy tiptoed his way towards Dean’s bedroom, slipping into the room and closing the door behind him. John wondered just how often this had happened whenever he was home, if it was a nightly occurrence.

\---

Dean smiled as Sam snuck into his room, pulling back the blankets. Sam slid under them, curling up against Dean’s body. Dean ran his fingers through Sam’s hair, pulling the younger boy against him, kissing him softly. Sam moaned into the kiss, grinding against Dean, needing more contact. Dean rolled them, placing kisses along Sam’s neck as his hands moved to unbutton Sam’s pajama top. 

Sam sighed happily as Dean began to undress her, needing to feel Dean’s body against her’s, needing to feel skin on hers. She was warm, so warm and needed the relief that only Dean’s kisses and touches could give her. Her hole was dripping wet, she needed to feel Dean buried inside of her, needed his knot tying them together once more. “Please, Dean, need you,” Sam whispered, shoving at her pajama pants, trying to get them off.

Dean had never seen Sam so needy before, had never before seen him trembling with want like this. Part of him should have realized that something was different, something was off, but all Dean could think about was getting inside of Sam, filling him up again and again. He yanked the pants off of Sam’s body, moving off of Sam only long enough to shove his boxers off before climbing back on top of him. His hands caressed Sam’s body, mouth kissing and licking and sucking marks onto Sam’s chest. “Sammy, love you,” Dean whispered, the head of his cock rubbing lightly against Sammy’s opening.

Sam spread her legs wider, whining with want. She needed Dean inside her and she needed him NOW. “Dean, please, inside, please,” she begged, body on fire, mind in a haze of lust.

Dean groaned, shoving inside of Sam in one quick motion. Sam always smelled amazing, but tonight, god, tonight Sam smelled incredible. Dean buried his face against Sam’s neck, thrusting hard. “God, Baby Girl, so good, always so good for me, Sammy. Smell incredible. Such a Good B.. Girl for me, fuck, Sammy.”

Sam chuckled, hands groping at Dean’s back, fingers leaving marks on his skin, “You were gonna call me a Good Boy, weren’t you, Dean?”

Dean kissed Sam, trying to distract him as he pounded into Sam’s body. Dean wrapped his fingers around Sam’s cock, stroking it in time with his thrusts. “Oh, fuck,” Dean said, voice rough and broken, feeling his knot begin to swell. This had never happened this fast before, something was different about this time. For starters, Sammy had never been this wet, this slick for him, Dean could feel Sammy’s wetness soaking the bed, and it turned him on more than he ever thought was possible. There was also the matter of his scent, it was like someone had taken Sam’s usual addictive scent and multiplied it by a thousand. 

Sam could feel Dean’s knot swelling inside of her, and groaned as it brushed against her prostate. The pressure was enough to set her off, causing her to come all over the two of them. She grabbed Dean by the back of the neck, kissing him hard, trying to silence her scream of pleasure. It had never been like this before, she was still so hard, so wanting. “Please, please, please, please, please,” Sam begged, not sure what she was asking for but needing more. She could feel Dean coming inside of her, filling her with his seed, his knot tying them together, as he came again and again. “Tell me, come on, Dean, tell me the truth, you almost, oh fuck, more, god more, you almost called me your Good Boy, fuck, Dean,” her words trailed off in a whine as her body began to shake, another orgasm ripping through her. It was too much, too fast, and Sam must have passed out for a little while because next thing she knew Dean was shaking her lightly, looking down at her with concern in his eyes. He was still buried tightly inside of her, his cock pumping what felt like gallons of come into her body.

“Sammy, you okay?” Dean asked, noticing Sam’s eyes begin to open. Dean had never seen Sam come twice in that short of time before, and as much as it freaked him out a bit, it kinda also turned him on a lot. Sam nodded at him, giving him a look that said in no uncertain terms that Sam wanted answers. Dean sighed, feeling Sam’s body tightening around him even more, a moan falling from his mouth. “God, yes, I’m sorry, Sammy. Didn’t mean it, didn’t mean to say it. I love you, just like you are, never gonna stop loving you. I love you no matter what.”

“Love you too, Dean. Mm, it’s okay, I don’t, oh fuck, right there, god yes, more, I don’t mind. I know I’m yours. No matter what you call me. God, Dean, so good, fuck.”

Dean nodded, kissing Sam gently. He rolled them on their sides, holding Sam against his chest as he continued to spill inside him. When Dean woke, the sun was up and he was still buried inside of Sam, knot holding them together. Sam’s skin had lost the fevered appearance it had had the night prior, and his scent was almost back to normal. Almost, but not quite, there was something there that Dean couldn’t place, but he was too tired to try and figure it out. He settled his head back against the pillows, drifting off once more.


	4. Chapter 4

It didn’t long, only a few short weeks, before John knew something was wrong. He’d been sticking around, deferring cases to other hunters, just so he could keep an eye on Sam and Dean. It wasn’t as if he didn’t trust them, but he’d been gone for over a year, long enough for them to have started a relationship while he was gone and John felt guilty over that absence. 

Sam had been getting more and more moody as the days passed, when he wasn’t getting sick that was, and John was almost at his wits end. He didn’t know how to deal with Sam, not anymore, and Dean wasn’t helping matters, as every time Sam and John fought Dean would glare at John before taking Sam up to their room. The two of them wouldn’t come out for hours, and John was well aware of what they were doing, as the two of them weren’t by any means quiet.

John spent his time researching, finding out all he could about Alphas and Betas. He wanted to understand his children better, and that meant finding out everything he could about them. At first he suspected that Sam’s mood swings were just normal teenager behavior, as Dean had been quite moody at that age, but as the weeks passed and Sam was sick on almost a regular schedule, John was starting to believe it was something else.

It wasn’t until almost five months after he had gotten home that he finally figured out what was wrong. Sam had stopped getting sick weeks earlier, but it hadn’t stopped the mood swings, if anything they had gotten worse. Add to that the fact that Sam hadn’t gone to school in a couple of weeks, locking himself and Dean in their room, the two of them only coming out to eat and use the bathroom. John was seriously considering leaving again, finding another long hunt to go on, just so he’d have a little peace. John had barely slept lately, the noises coming out of his children’s room too much for him to handle. 

Finally, John had had enough, and in a lull between the two of them going at it John ordered Sam and Dean downstairs to talk.

Sam looked at her father, defiance written on her face as she looked at him. She crossed her arms over her stomach, trying to hide the growing bulge. It really hadn’t taken her long to realize she was pregnant, though Dean and her had yet to inform their father of that fact, but the man wasn’t blind and Sam would soon be to big to hide it for much longer. Dean had been her rock lately, keeping her grounded, keeping her sane when she had began to freak out over getting pregnant. He promised her that no matter what he’d always be there for her, and she trusted him to keep his word. 

Dean knew what was coming, knew that their father had probably figured out what was happening. Dean was scared and excited. Sammy was having his baby, they were going to be parents in less than four months and Dean wasn’t sure either of them were ready for that. He wrapped his arms around Sam’s shoulders, giving him a quick kiss on his temple before turning to face their father.

“How far along are you, Sam?” John asked, just getting straight to the point, not sugar coating it. He could see Sam flinch, watched as she reached out for Dean’s hand, watched Dean squeeze it gently.

“Five months, about, I think,” Sam said biting her lip. She looked down, not wanting to see anger or disgust on her dad’s face.

“Sam, look at me,” John said softly. When he did John gave him a small, calming smile. “I’m not mad, kiddo. I just wish you two would have told me so I could help you out. I remember how scared and worried your mother was when she was pregnant and I can only imagine what you are going through. I want to help, Sam, you’re my kid.”

Sam was floored, she had thought that their father would have been pissed off to know about the pregnancy, but there was no anger in his voice, only love. 

Dean looked like a weight had been lifted off of his shoulders and he gave a sigh of relief. He wrapped his arm even tighter around Sam, smiling as his mate rested his head against his shoulder. “Dad, we didn't plan on this...”

John nodded, giving a tired little smile. “You two have to be honest with me. Five months ago things were different, weren't they?”

Sam nodded, a bit nervously, “Yeah, it was more intense. I needed Dean, like I felt like I would die if I didn't have him.”

“You went into heat, Sam. No one is quite sure what causes heats. Sometimes they run like clockwork, sometimes they are brought on by stress, sometimes they just happen for no apparent reason. It was right after I found out, wasn't it?”

Both Dean and Sam nodded, realization coming across their faces. 

“It was odd, in a good way, but still odd. I mean, fuck, never been like that before,” Dean said, a bit of a blush coming to his cheeks. He wasn't embarrassed or ashamed of what they did, not really, but talking about their sex life with their dad made him a tiny bit uncomfortable.

John ran his hand over his face, sighing a little, “Now while this isn't how I'd hoped to eventually have grandchildren, what's done is done. Have you gone to see a doctor yet, Sam?”

Sam shook her head, looking down at her feet. 

“I'll call and set up an appointment for you. Hey, look at me, I'm not mad, okay. I just have to get used to this. I know you're probably scared, both of you. I want to help.”

Dean swallowed hard. He had been certain their father wouldn't have been as supportive as he was being. It was one thing to know that your children are mated, it was another thing entirely to find out your children are expecting parents. “Thank you, Dad,” he whispered, giving an honest smile.

\---

They were able to get an appointment set for less than a week later. Sam spent most of the days waiting in a nervous state. She was scared, afraid that something would be wrong with the baby, afraid that the doctor would think the worst of Dean. But through the wait Dean was there for her, as always, holding her close.

Having Dean's support helped, as well as having her father's as well. She knew that John still had some issues with her and Dean being involved, with her being pregnant by her big brother, but he was doing his best.

The appointment went smoothly, and Sam and Dean were assured that their babies were fine and healthy. Sam felt like she was about to faint when the doctor had said babies, plural, as in she was carrying twins, but Dean had held her hand and kept her with him.

When the doctor said that Sam was expecting twins Dean had been shocked, but he needed to stay strong for Sam, needed to keep himself calm. He was glad that their father had driven them to the appointment, as he knew he was in no shape to drive, and while Sam could drive, he wasn't legal. They decided not to find out the sex or sexes of the babies, wanting to be surprised.

The ride home was almost in silence, Sam and Dean both too dazed and shocked to say much more than “Twins” to their father after leaving the doctor's office. John had scheduled a follow up for Sam, knowing by the looks on Sam and Dean's faces that neither of them would think of that. 

They pulled into their driveway, and all three Winchesters were pleasantly surprised to see Bobby Singer sitting on their front porch. The look on his face when Sam stepped out of the car was priceless.

John cleared his throat, greeting Bobby, “It's good to see you, Bobby. What brings you to these parts?”

Bobby shook his head, realizing he was staring. “I have some news you all might wanna hear.” He nodded at Sam, “Congratulations, I see.”

Sam grinned, leaning against Dean a bit, “Thanks, Bobby. We just came from the doctor's.”

Dean nodded, giving a little grin, which spoke of both his happiness and a trace of fear, “Twins.”

“You're the daddy?” Bobby asked, not really sounding too surprised. The Winchester kids had always been overly close.

Dean nodded, grinning sheepishly, “Yeah, I'm the daddy.”

John walked towards Bobby, speaking quietly, “They're mated, Bobby. Dean's an alpha and Sam's a beta.”

Bobby's eyes widened at that. In all the years he had known the Winchesters he had always thought that Sam was a girl. But finding out that not only was Sam a beta, but that Dean was an alpha and mated to Sam made Bobby a bit less concerned about their relationship. Yeah, it wasn't the norm for siblings to get involved, most of the time that was frowned upon. But not with alphas and betas. When that happened usually no one batted an eyelash. 

What Bobby couldn't understand was why Sam had been raised as a girl. It wasn't until puberty that it would come out if someone was an alpha or a beta, and yet Sam had grown up as his surrogate niece. He looked at John, shaking his head a bit, “You'll explain?”

John nodded, walking inside, Bobby, Sam, and Dean following. “So you have something to tell us?”

“You all might want to sit down. The news I have is pretty big. A few days ago I ran into a hunter, one I've never met before. We ended up talking and she asked if I knew how to get ahold of you, John.”

“She? So what's this hunter's name?”

“Before I tell you, I gotta tell you what she told me. She said she didn't want to do what she did, that it was the only way to protect her kids.”

John's eyes widened at those words, “No, you don't mean...”

Bobby nodded, reaching into his pocket to pull out a photo of the woman, one she had given him to show to John. “She said her name was Mary Campbell. She told me to show you this.”

John took the photo, eyes widening even farther. True she was older than he had last seen her, but there was no doubt in his mind that the woman in the photo was his dead wife, well obviously not so dead as it would seem.

“I told her I'd let you decide if you wanted to get in contact with her. I have her number. When I put two and two together about who she was I did checks, holy water, silver, everything. As far as I can tell she's the real deal, John.”

John didn't know what to say. He ran his finger over the face on the photo, whispering her name, “Mary.”

“Our mother's alive?” Sam asked Bobby, confusion on her face.

“Unless this is someone or something's sick joke, yeah, I think she is, Sam.”

“Call her. Tell her to come here, tell her... Don't tell her about Sam and Dean being mated, or being an alpha and a beta, or that Sam is pregnant. She can find that out when she gets here. Just... just get her here, Bobby.”

The other hunter nodded, walking into the kitchen to make the call.

Dean put a protective arm around Sam, taking a deep breath, “She better have a damn good explanation. After all this time...”

Sam bit her lip, voice shaky, “I finally get to meet our mother. I just hope...”

“She'll love you, Sammy. She'll accept you, accept us. If she doesn't... then that's her problem. We've lived this long without her. But if she's like I remember she'll love you unconditionally.”

Bobby walked back out of the kitchen, clearing his throat, “She'll be here in two days.”


End file.
